Check if string is empty or all spaces in C#

If you have .NET 4, use the string.IsNullOrWhiteSpace method:

if(string.IsNullOrWhiteSpace(myStringValue))
{
    // ...
}

If you don’t have .NET 4, and you can stand to trim your strings, you could trim it first, then check if it is empty.

Otherwise, you could look into implementing it yourself:

.Net 3.5 Implementation of String.IsNullOrWhitespace with Code Contracts